Stem making machine



- Feb. 23, 1932. 0 Y AL 1,846,025

STEM MAKING MACHINE Filed Dec. 11. 1925 2 SheetsSheet l ii llilllllllll M INVENTOR. GEORGE COBY E12NEJTKAU5Q ATTORNEY.

G. COBY ET AL.

STEM MAKING MACHINE Filed nee.

'Feb. 23, 1932.

FIGA.

' F SG. 10.

IN V EN TOR.

ATTORNEY.

Patented Feb. 23, 1932 UNITED STATES PATENT OFFICE GEORGE C0131 AND ERNEST KAUER, 0F CRANSTON, RHOI JE ISLAND, ASSIGNORS TO C. E. MANUFACTURING CO., 0.? PROVIDENCE, RHODE ISLAND, A CORPORATION OF RHODE ISLAND STEM MAKING MACHINE Application filed December 11, 1925. Serial No. 54,681.

Our invention relates to the manufacture of tipless radio vacuum tubes, incandescent lamps and other scaled electrical devices and more particularly to stem heads of machines used in such manufacture. The invention may, in fact, be used in combination with or as an attachment to any of the well known types oi stem making machines now in use. The invention is adapted to hold and support the assembly of parts from which are made the stems of such tipless lamps and radio tubes and to perform the operations of heating and pressing the glass of the stem tube about the lead wires and formation of a union between the exhaust tube and the stem tube and of a passage through the stem tube communicating with the exhaust tube. In addition to this it comprises means for glazing the end of the exhaust tube simultaneously with, and as a part of theoporation by which the passage through the stem tube is formed.

T he stems of incandescent lamps and tubes are manufactured upon so-called stem making machines. These machines are of various types, but all comprise a revolving table or frame, upon which are mounted, one or more heads adapted to hold the assembly of stem parts and to move the said as sembly into various positions of the machinewhere the operations comprised in stem making are performed. A very generally used type of stem making machine has six heads so mounted and the rotating table mo We each head through six positions. The parts trom which the stein is to be made are placed upon the h ad when it is in the first and second positions. llhese parts consist ot' a piece oi flared tubing, called the stem tube, the lead wires and in case of stems for tipless devices, a tube of smaller diameter than the stem tube arranged concentrically within the stem tube. The head itself comprises a frame mounted on a sleeve t post. blupporteduponthis frame are a die block adapted to hold, the assembled parts from which the stem to be made, a pair of jaws to clutch the stem glass in place on the die block and a second pa1r of jaws, called press awe, set at right angles and hold it is required to open it and remove the finished j stem when the head is in the last position At the first posltionthe operator feeds the parts to make the stem. When this is completed the head. moves to the next position where it pauses between two or more blow pipe fires, the flames of which meet and focus on the lower portion of the stem tube. After a suitable heatinghere the table revolves and carries the head to the next posit-ion Where a further heating takes place, the stem head pausing between two groups of fires, one

group on each side. In the fourth position tour or more blow pipes on each side focus upon the lower portion of thcstem tube. In this position the glass of the heated portion oi the stem tube has become soft and almost fluid and two pressing jaws attached to the stem head clamp this soft glass, pressing it into a flat air tight seal about the lead wires. In the fifth position a single fire prevents the too sudden cooling of the glass and it is in this position ordinarilythat, in the case of stems for tipless devices, an air jet arranged so as to come inalignment with the exhaust tube which is held. by a clutch within the stem tube, blows a current of air through the eizluiust tube and through the softened glass of the stem tube thus forming an open passage through which the device maylater be exhausted of air. In thelast position the operator removes the finished stem from the head.

It is the object of the present invention to provide a clutch adapted to hold the exhaust tube concentrically within the stem tube and automatic means for opening the same in order that the finished stein may be removed at the end of the stem making operations.

It is a further object to provide a means by i which the exhaust tube may be sealed to the stem tube, a passage blown through the stemyention comprise a clutch of a novel construction mounted upon the stem head and a cam afiixed to the central post about which the table revolves. Gas and air ducts arranged at the sixth position so as to blow a sharp jet of flame through the exhaust tube and a soft 'fiame against'the portion of the stem tube wall where the exhaust tube has been sealed on, perform the operations of smoothing the outer end of theexhaust tube, puncturing the wall of the stem tube and glazing the joint.

- The inventionwill beclearly understood by'reference to the drawingsin whichFig.

1 represents partly diagrammatically'a stem head completewith the exhaust tube clutch of our invention attached; Fig. 2 is a view of the stem head and clutch taken at right angles to .the v ew in Fig. 1; Fig. 3 diagrammatically'shows a detail of the exhaust tube clutch and the cam by which it is opened;

Fig. 4 diagrammatically shows a plan view of the bedof the stem making machine with 'the revolving table having six stem heads mounted thereon Fig. 5 is a detail of the flame nozzle; Fig. 6 shows the exhaust tube "in the preferred form; Fig. 7 is an eleva-' jtion showing the assembly of stem parts in place on the stem head in position S; Fig.

8;.shows the assembly in position S Fig.

' 9 shows the heating operation in posit-ion S Fig. 10 shows the operations of heating and sealing the exhaust tube to'the inner wall of the stem tube and the pressing of the seal which are simultaneously formed in position S; Fig. 11 shows the operations of glazing,

annealing and formation of the passage of the exhaust tube through-the stem tube which are simultaneously conducted at position S Fig. 12 shows the finished stem as it is released from the exhaust'tube clutch in po 'sition S.

Referrlng now to' the drawings, A is a frame terminatingat the lower end in the sleeve, A, through which the rod, B, moves. At the top of the rod, B, is fixed the double link, O, to which are pivoted the arms, D and I). The clamping jaws, E and E, are pivoted to the lugs, F and F, which are fixed to the upper part of the frame, A. To the clamping jaws, E and E, are also pivoted the arms, D and D. A post,G, set in the frame, A, supports the exhaust tube holding apparatus which isshown in detail in Fig. '8. A die block, H, is set into an orifice in the "top of the frame, A, and there fastened, by'

'meansof a'set screw or. other means.

protrudes On the stem head, as will be seen by reference to Fig. 2, stem holding jaws, K, are aflixed. A spring, L, serves to hold the jaws closed and they may be opened by pressure exerted upon the pressure pieces, M and M. The stem-head either singly or with a number .ofother similarly constructed stem heads is set into the revolving table of the stem making machine, the shoulder, N, resting upon the table and the sleeve, A, being set into an opening adapted to receive it through the table, O, so that the end of the rod, B, below. At the pressing position, shown in Fig. 4, at S, a cam beneath the table, O, causes the rod, B, to rise, thus closing the clamping jaws, E and E, so as to form the press of the stem. After the press is so formed the cam permits the jaws O and E to open again.

As will be seen by reference to Fig. 3 the exhaust tube holding apparatus consists of a supporting bar, 0;, on which is mounted a pair of jaws, 2), operating in scissors fashion which are held shut by the spring, 0. The supporting bar, a, is aflixed to the post, G, of the stem head by the set screw, 71., as shown in Figs. '1 and 2, and at the opposite end of the bar-is av pivot, 01. The arms, 6 and are rigidly connected in angular relation to each other and pivoted at the point of union-to the supporting bar, a, by the pivot, d. The arm, 6, carries at its outer end a roller, g.

Atthe extremity of the arm, f, is fixed a post,

In Fig. 3, the roller, 9, is shown contacting with the cam,.Q, which is afiixed to the and U, consist of single blow pipes placed on opposite sides of the position. At S double blow pipes T and U are placed oppositely and at S, quadruple blow pipes are similarly positioned. The fires of all these blowpipes focus atthe lower extremity of the stem tube supported on the die block, H, of the stem head and the revolving table, O, causes the heads to pass between them. Two addi tional fires, one, V, preferably at position,

S and one, V, preferably at position S are positioned a little higher than the other fires so that their flames impinge against the wall of the stem tube at a point above the press, which is formed at position, S 2. At

position, S, a pipe, X, carries air and gas. under light pressure to a nozzle over the exhaust tube of the stem upon the head in that position. The pipe, X, carries gas to a pilot light provided'to keep the gas burning constantly at the nozzle of X. This nozzle and the pilot light are shown in detail in Fig.5.

'Lal

In Fig. 5, a length of rubber tubing, is, connects with the gas and air pipe, X, shown in Fig. a at position S A burner, m, at the end of the rubber tubing, 70, carries a flame constantly burning and the metal disc, Z, serves as a shield preventing the flame at the end of the burner, m, from meltin or burning the rubber. A gas line, a, is ept burning so as to relight the flame at min case it should become extinguished. Projecting down from the burner, m, a locatingdevice consisting of a wire hook, 0, engages the end of exhaust tube of the stem and brings it in line with the fire of the burner, m.

Having thus described the various parts of our invention we will now explain its operation. An operator at position, S, of the revolving table, inserts the lead wires into holes in the die block H, of the stem head which at the moment is in that position. The table then moves, bringing this stem head to position, S, where it stops. Another operator at this position, places, the stem tube, a piece of flared glass tubing about the lead wires with the flared end of the stem tube up. This operator then forces a glass exhaust tube of smaller diameter than the stem tube and preferably bent at one end as shown in Fig. 6 into the jaws, 7), of the exhaust tube holding apparatus. The operator then pushes the exhaust tube into the stem tube, thus forming the assembly of parts shown in Fig. 7 and the head moves successively through positions, S S and S. In these positions the fires, T and U, T glass of the lower end of the stem tube. At position 8*, the lower part of the stem tube has become so soft that it has begun to fall in against the lead wires. In this condition, a cam under the table, 0, causes the rod, 13, to rise and fall back. In rising, the rod, B, lifts the arms D and D, and these clamp the jaws, E and E, against the soft part of the glass stem tube, thus forming a flat glass seal or press about the lead wires. The operation performed at positions 8', S and S are illustrated in Figs. 8, 9 and 10.

lVhile the head is in position 8*, the fire, V, which as has been stated is raised slightly above the fires, U impinges against the stem tube a little above the press and at the point where the bent end of the exhaust tube touches the wall ofthe stem tube. The effect of this fire is slightly to soften the glass of the stem tube and the end of the exhaust tube and seal them together (Fig. 10). It does not, however, unless desired, puncture the stern tube wall so as to form a passage through communicatingr with the exhaust tube. This passage is formed at the next position S where the pipes, X and X, blow a flame down through the exhaust tube and against the stem tube wall from the inside while the fire, V, projects against the outside of the stem tube Wall at the same spot (Fig. 11

and U and T and U soften the These two flames, X" and V ,cooperate to form a puncture through thewall of the stem tube communicating with the passage of the exhaust tube. Moreover the flames from the pipes, X, and the fire V each perform additional individual functions of importance. The flames from the pipes, X, striking against the upper lip of. theexhaust tube as it is blown into that tube, smoothes or glance the lip. This is a matter of importance When the lampor radio tube is connectedwith the pumps for the exhausting .operation as it enables the operator to insert the exhaust tube into the rubber pump connections without cutting them. fire from V anneals the glass ofthe stem. By means of an economizer synchronized with the revolving table, 0, the fires, X a and V, may be timed and the period during which they play may be lengthened or shortened: as required.

The stem head then moves from which it started. At this position the roller, 9, of arm, 6, of the exhaust tube holding device, comes in contact with the cam, Q, which is fixed to the center post, R of the machine. The roller, g, rides on thecam,Q, and the arm, 0, is forced back by the cam, turning on the pivot, d, and forcingthe post, 2', of the arm, 7, comprised in the clutch, 6, thus opening the jaws of the clutch and releasing the stem tube. The operatorat the clutch, K, by pressure "upon the. pressure pieces, M and M, and removes the completed stem from the head, whichyis nowready to repeat the operation. i i

The invention, comprising as it does a means of automatically operating the exhaust tube clutch and automatically sealing the exhaust tube to the stem tube and formingthe exhaust passage through the stem tube walls, is adapted for use in combination with any of the types of stem making machines now in use. It is obvious that the elements of this invention may be differently arranged upon machines of different types without departing from the principle illustrated. We have set forth hereinabove the application of the invention to one well known type of stem making machine, but desire it to be understood that it may have other embodiments and we do not desire to be limited to the construction shown in the drawings.

Having thus described our invention what we claim is:- a. 1. In a machine for making stems for. incandescent lamps and similar articles, the combination of a rotating stem head mounted uponsaid machine; aclutch comprising. two

members pivoted in scissors fashion and mounted on said stem head, said clutch being adapted to hold an exhaust tube in position in an assembly ofstem parts. supported upon said stem head; a pair of arms rigidly, fixed On the other hand, the

to position between the two elements position S then opens a to tube and lead in 7 said exhaust tube and p v q controlling the time during which said second 5 edito move said arms on their pivot and force said post within the clutch members when the said clutch is brought into operative position with'respect tosaid cam the rotation of.

the stem head.

'2'. Ina head. of a stem making machine, the combination of a clutch adapted to hold an 'exhausttube, said clutch being mountedion a support-and consisting of two members, piv- -oted in scissors fashion to said support and a spring holding said members shut; and a pair of arms rigidly united in angular relationto each other and pivoted to support at vthepoint of union of said arms, one of saidarmscarrying a post adapted to enter betweenthe ends of the pivoted members of said clutch.

'3. In a. stemmaking machine, the combination of a revolvingtable; a plurality of stem heads mounted; upon said revolving table,

each stem head having means to support an assembly ofstem parts comprising a stem tube and an exhaust tube; a system of fires so pos1; tioned as to focus upon the lower portion or the saidstem tube as the stem heads rotate between them a second system of fires so positioned as to {impinge agamst said stemtube at a desired point above sa1dv first system oi fires; and'afire nozzle-adapted to direct a flame through said exhaust tube;

4. In a stem making machine, vthe combination of arevolving table; a plurality of stem heads mounted ble, each stemchead having; means to support an assembly. ofstem parts comprising a stem said stem head adapted to hold an exhaust tube; automatic means for releasing said errhaust tube from said clutch; a system of fires -so positioned as to focus upon the lower portion of'said stemtube as the stem heads rotate between them; a second'system of fires so positioned as toimpinge againstsaid stem 1 tube at'a desired polntabove said first system of fires and a fire nozzle adapted'to direct a flamethrough said exhaust tube. v r

5. In "a stem making machine a systemof fires so positioned as to focus upon the lower portion :of an assembly of stem parts supported upon adie block of a stemhead of said machine; a second system of fires adapted to seal the bent end of an exhaust tube-to the inner wall of a' stem tube 'in' said assembly; a fire nozzle adapted to direct a flame through automatic means .for

vacuum tubes and similar articles, the combi- I nation of means for supporting a stem tube;

means" for holding withln said stem tube a said clutch upon said revolving ta- Y.

wires; a clutch mounted upon the lower-end vofsaid fused portion of said stemtube to form apress and causing the bent end of sa1d exhaustjtubeto protrude through the softened wallof'said stem tube above said press separate heating means for using the protruding end of said "exhaust tube with said stem tube; and means for open ing the passage throughsaid exhaust tube.

7. In a glass-working machine, the combination ofineans for holding a glass tube; means for holding a second glass tube of smaller diameter in such a position within said first tube thatthe end of said second tube contacts with the inner wall of-said first'tube; heating means for fusing the outer wall of said first tube opposite the pointof said contact, by causing the walls of said first tube to soften and collapsegagainstthe-bent end of said first tube and permitting said" bent end to' protrude through saidfirst tube; separate heating means for fusingthe protruding end 7 of said second tube with the wallof said first sealed end ofsaid' exhaust tube. 1 y

9. In a head of a stemmaking machine a clutching device adapted to hold an exhaust tube having a bent end in such a manner that.

said bent end is positioned within and-in con tact with the inner wall of a stem tube supported upon said head, said clutch being .mountedon a support and consisting of two members, pivoted in scissors fashion to said support a spring holding said members shut two arms rigidly connected in angular relation to each other, and pivotally mounted at the point of union to said support; at the extremity of oneof said arms a post acting between [the pivoted scissor members and at the extremity of the other ofsaid arms a roller adapted to ride upon a cam afliXed-in a definite position to a post at the center of said stem making: machine; and means to rotate said stem head so as to'b *ing the roller atthe extremity of said arm into operative position with said cam.

10. In ahead for a stem making machine,

- the combination of a clutch comprising two members pivoted inscissors" fashion and mounted on said head, sa1d clutch being adapted to hold an exhaust tube in position in an assembly of stem parts supportedupon 'said'head; a pair of armsrigidly' fixed in angular relation to each other and revolving bent exhaust tube of smaller diameter in coni tact Ywith theinner sidewall of saidstem tube around a. pivot at the junction thereof said pivot being fixed upon said clutch mount; one of said arms carrying a post adapted to force apart the members comprising said clutch when the other of said arms moves in a direction toward said clutch around said pivot.

11. In a stem making machine, the combination of a circular table, means for revolving said table about its central points, a plurality of stem heads mounted about the periphery of said table, each stem head having means to support an assembly of stem parts comprising a glass stem tube and an exhaust tube positioned within said stem tube so as to contact with th inner wall of said stem tube; a plurality of heating elements mounted on a stationary frame beyond the periphery of the rotating table adapted to fuse the lower portion of said stem tube; a second system of heating elements adapted to project fires so as to impinge against said stem tube at the point where said exhaust tube contacts with the in ner wall of said stem tube and means adapted to direct simultaneously a flame through said exhaust tube in opposition to said second system of heating elements.

In witness whereof, we hereunto subscribe our names this l th day of November, 1925.

GEORGE COBY. ERNEST KAUER. 

